Temperature conditioning system method to optimize vaporization applied to cooling system

ABSTRACT

Described herein is for a system and procedure to apply vaporization for heat transfer processes, particularly condensers in air conditioning and refrigeration systems both for upgrading units using the discontinued R22 refrigerant and for new equipments. The application can be applied to other cooling processes such as computer chip cooling, garments for medical, personal garments for military personnel. The application points to the features of different manifestations of vaporization for cooling in both natural and other equipments. The process can be extended for small and compact implementation on new equipments with maintenance improvement compared to water tower coolers, lower capitalization costs, modularity and ease of maintenance, and indoor installations enabling extension of capability of the cooling system with application of air flow condition. The advantages and implementation on new equipments for residential, industrial and large cooling units enable several advantages both economic, reliability, maintainability, indoor operation, reduction of cost of scaling problems and flexibility. Many additional applications are possible and are discussed herein, including high power computer chip cooling.

CROSS REFERENCE RELATED APPLICATIONS

This application has priority to currently pending U.S. ProvisionalApplication Ser. No. 61/335,474 filed on Jan. 7, 2010 titled TEMPERATURECONDITIONING which is hereby incorporated by reference in its entirety.

FEDERAL SPONSORED RESEARCH

None

SUMMARY

This application is a method to optimize the application of vaporizationfor cooling purposes. The process is applied in this application forupgrades on air conditioning and refrigeration systems to improveefficiency with extension of the performance on the effect of ambientenvironment temperature and humidity. This feature would yield asignificant improvement in energy usage in locations where thetemperature and humidity are high where the equipment undergoes veryhigh usage. The added cooling capacity due to the improvement inefficiency could be strategically used to improve comfort level with theattendant advantage of reducing energy because of the possibility ofraising the temperature control setting.

The process also is applicable to new equipments where the newrefrigerants and techniques are applied. Application of the process forthese higher efficiency units benefits at a higher rate than the upgradeby the ratio of the COPs of the new to the old systems.

Application to new systems results in reduction in initialcapitalization besides the savings on recurring cost and maintenancecost. Another embodiment presented for this cooling process is toimprove performance and maintain reliability of computers, both personaland supercomputing architectures by cooling the computer chip.

The known practical limitations of vaporization are addressed in theprocess. Vaporization of water applied to cooling processes isaccompanied by scaling. Scaling is the buildup of both bio film andcarbonate deposits in slow water flow around heated surface of metal.The process decreases and simplifies the maintenance requirement due toscaling because of metering of the water delivery for vaporization.

The process results in the following benefits. The efficiency forcooling, the reduction of scaling with improvement in both economics andlogistic of maintenance, extension and improvement of the range ofambient environment conditions for the air conditioner or refrigerationsystems and the computer chip cooling. The process introduces othercontrol parameters that enable the capabilities mentioned. Inparticular, this application presents an airflow temperature andhumidity control such that the limitations because of ambienttemperature and relative humidity to perform required cooling especiallyfor large loads are alleviated with further improvement in systemefficiency. The reduction in the demand for air flow enables bringingthe condensing equipments indoor and enables other control strategies toachieve system efficiency, maintenance, reliability performance.

This application is for a procedure to apply vaporization for heattransfer processes, particularly condensers in air conditioning andrefrigeration systems both for upgrading units using the discontinuedR22 refrigerant and for new equipments.

The application can be applied to other cooling processes such ascomputer chip cooling, garments for medical, personal garments formilitary personnel.

The application points to the features of different manifestations ofvaporization for cooling in both natural and other equipments. Theembodiment cited for upgrade of air conditioning and refrigerationsystems that are using R22 and other refrigerants. These arerefrigerants disallowed for new equipments by EPA. The process isdiscussed in detail to show the effective improvement in efficiency,cooling capacity, ambient temperature of operation. The process can beextended for small and compact implementation on new equipments withmaintenance improvement compared to water tower coolers, lowercapitalization costs, modularity and ease of maintenance, and indoorinstallations enabling extension of capability of the cooling systemwith application of air flow condition.

The advantages and implementation on new equipments for residential,industrial and large cooling units enable several advantages botheconomic, reliability, maintainability, indoor operation, reduction ofcost of scaling problems and flexibility.

The implementation of the whole gamut of listed advantages presupposesthe development of embedded controllers and digital interface devicesfor sensors, drives and communication.

The other embodiment is for high power computer chip cooling. Theembodiment on computer chip allows the cooling of 1 kilowatt per squarecentime computer chip heat dissipation with reduced air flow volume andheat sink physical volume.

The application is on heat transfer. The process is an optimizationprocedure for the heat transfer that uses the common processes ofconduction, convection, radiation and reflection.

Conduction is the process by which the energy of a source which isusually manifested by the temperature of the material is routed out viathe material or other materials through the passage that allow theenergy in the form of “heat flux” to the recipient or absorbingmaterial. The process is dependent on the material property of thermalresistance which is inversely proportional to the area the flux wouldflow and the length of the path or thermal path.

Convection is the actual transport of materials that have acquired theenergy from the source. The transport of the material enables the flowof the heat flux. The usual convection medium is air where the airaround a highly conductive material like the enclosure for therefrigerant acquires the heat energy by conduction. The thermalresistance of the air and also the specific heat which is the amount ofenergy needed to raise its temperature one degree per unit weight isrelatively low. Therefore the method of convection demands a largeamount of air mass to be transported.

Radiation is a transport phenomenon similar to the convection process.However in this case, there is no material that is physicallytransported. The energy of radiation is in the form of electromagneticwaves that is able to be conveyed even in vacuum or space. The energy ismanifested and proportional to the fourth power of the temperature ofthe source.

The application shall discuss only the conduction and convection heattransfer process. The convection process uses water as the transportmaterial.

The vaporization of water has been applied for cooling for over severaldecades in air conditioners and refrigeration equipments. Vaporizationis also a natural phenomena associated with our weather and life onearth. The vaporization in vegetation and open waters are primarycontributors for our weather.

The vaporization of water involves a large amount of energy. Under theusual situations where the pressure is at one atmosphere, the amount ofenergy to vaporize a gram of water is 2260 joules. This is quitesignificant when compared to the sensible heat needed to change a gramof water by one degree centigrade, which is 4.18 joules per gram perdegree C. In the case of air, the sensible heat absorbed by air is verysmall, 0.001 joules/cubic centimeters. FIG. (3) shows the typicaltopology of cooling a material. It uses material property that enablesthe diffusion of heat energy along the material. The degree ofefficiency of conduction is determined by the thermal conductivity pathfrom the material to be cooled to the next material. This metric isdependent on the material and the physical dimensions. In particularmetals are very good heat conductors and the heat flux is improved byincreasing the area for which the heat flux flows and by reducing thelength of the path involved in the flux passage. The second normalmedium is air because it serves as a medium of transport for the heatenergy to the ambient environment by convection. The higher temperaturefrom the “heat sink” is acquired through the conduction of heat from themetal surface to the air. This starts the diffusion process. The regionbetween the heat sink to the distance where the ambient temperature isacquired is usually called the boundary layer. This layer under steadystate conditions establishes the effective thermal conductivity from thesecond interface to the ambient air. Since the boundary layer is airwhich has very low thermal conductivity, the effective resistance of theboundary layer is large. The high thermal resistance of the boundarylayer is minimized by modifying the thickness of the boundary layer.This is achieved by the process of convection where air flow withambient temperature reduces the thickness of the boundary layer byremoving the warm material on the boundary layer. The boundary layer isbetween the surface of the metal surface and the edge where the boundarylayer reaches the temperature of the ambient air temperature. Theboundary layer temperature profile is dependent on the effectivediffusion process modified with the convection transport mechanism. Ifthe diffusion gradient is maintained with the air flow, then continuoushigher heat flux flow occurs. The efficiency of removing the warm airfrom the boundary layer is obviously dependent on the velocity of theair flow and the temperature difference between the second interface andthe ambient temperature. The practical limits therefore are theeffectiveness of the air flow for removing the heated mass of air. Thisaffects the efficiency of the system because a higher air flow meansmore power usage for the fan. Raising the air flow velocity causeshigher noise levels.

The resulting thermal resistance of the boundary layer imposes practicallimits for higher cooling capacity. For example computer chips needcooling requirements around 150 watts. The silicon chip technology isimproving and following Moore's law on speed and feature sizes. Atpresent, the power levels that is possible with the feature sizes of thesilicon devices developed by the technology and the natural desire tointegrate as much as of the system in the chip is predicted requires atleast 1 kilowatt per square centimeter for cooling. The present coolingtowers that require cooling for 150 watts and uses heat pipes and finsthat occupy over 100 cubic inches with attendant noisy fan for air flow.The present technology for the cooling requirement would demand a largemass of air to transport the needed heat and larger physical size andother complication plumbing if heat pipes were applied. The applicationaddresses these practical problems.

Processes Using Vaporization for Cooling

This application is the process of modifying the process discussed abovewith the use of water as the medium that is created and removed from theboundary layer. The process applies a similar structure as used in priorart technology of using conduction and convection of air to convey theheat energy absorbed with the air flow to the environment. The specificheat of the air is 0.001 joules per cubic centimeter. Water whenvaporized to form the boundary layer extracts 2260 joules per gram forcooling. The process uses water that is vaporized by the introduction ofwater on the interface from the high conductivity heat sink to carry theheat energy to ambient environment. The vaporization of water involvesthe large heat and requires only a small amount of water to support thecooling process. For example, if the heat sink is to provide cooling forone kilowatt, the water needed is less than one half (½) grams per sec.Air however can support a limited amount of water vapor that isdependent on the air temperature. The capacity of air to support watervapor product of cooling is limited and increases as an exponentialfunction of temperature.

The process of vaporization is the separation from the liquid to vaporof very high energy molecules. The rate by which this occurs isdependent on the temperature. The temperature establishes the density orthe vapor pressure created from the surface of the water film at thegiven temperature. The vapor pressure created at the immediate boundaryfrom the source of heat to the air continues receiving higher energymolecules up to the level determined by the saturated capacity of theair. At this state, the amount of molecules leaving the liquid state arethe same as the amount converted back to liquid. The relationshipbetween the maximum water vapor content for a cubic meter of air iscalled saturated humidity and is dependent on the air temperature. Therelationship is exponential with increasing temperature. FIG. (1) showsthis relationship. When the saturated condition of the water vapor isreached, the heat flux is reduced. If the container is enclosed, theheat flux completely stops because there would be zero nettransformation of water molecules from one phase to the other. If theenvironment is not enclosed, the boundary layer laminar sheets undergodiffusion process because the concentration of water vapor immediate tothe heat source is much higher initially than the succeeding layers fromthe metal or water film surface. The water vapor in the air is usuallylower than the maximum it could support called the saturation content.The ratio of the water vapor to the saturated level is called therelative humidity. The dew point of air is the temperature where thewater vapor content starts condensing, that is when the water vaporcontent of the air is equal to the saturated air. FIG. (1) shows thesaturated humidity and also the amount of water vapor available beforesaturation when the relative humidity is 40%.

If one were to assume for example initially that the next layer to thesaturated layer from the water film were at the vapor pressurecorresponding to the incoming air flow then a large difference wouldexist because of the probability that the immediate surface to the waterfilm would be saturated. This difference in vapor pressure createseffective diffusion mechanism where the water vapor content on theimmediate area from the water film surface migrates to the lower watervapor density layers. This process continues outwards perpendicular tothe surface until the steady state boundary layer is established and theheat flux flow is dependent on the vapor pressure gradient created bythe diffusion. This is dependent again on the corresponding differencebetween the saturated vapor pressure at the temperature and the vaporpressure presented from the ambient air flow. Note that the transport ofthe water vapor to create the heat flux flow is not dependent so much onthe temperature but primarily on the vapor pressure gradient along theflux path. The main parameter is that the diffusion gradient isestablished and determines the capability of the supporting heat sinkcircuit to convey the heat flux. When steady state is reached withoutair flow, the air chamber would reach the same temperature as the heatsink interface. The introduction of air flow to facilitate convectionremoves the water vapor from the chamber. This completes the flow ofheat flux from the heat source to the ambient environment. This isenhanced when there is convection to transport of vaporized water. Theair flow removes the vapor material in the chamber and creates a thinboundary layer between the heat sink and the incoming air flow. Theboundary layer is sustained with higher continuous heat flux from thesaturated interface of the water from the heat sink when the boundarylayer gradient is maximized. If the heat flux increases, the vaporgradient has to correspondingly increase such that the flux isaccommodated. The air flow therefore has to be high enough such that thevapor generated does not accumulate to the level of degrading the heatflux flow needed. The process is dependent on the diffusion created bythe difference in vapor pressure or gradient of the water moleculeconcentration starting from the interface to the effective region wherethe air flow transports the water vapor. The thickness of the boundarylayer is reduced depending on the air flow velocity. This improves theefficiency of transporting the water vapor cooling product. Thediffusion process implicitly creates a temperature gradient. However themagnitude is minimal. Thus the difference in the sensible temperaturechange between the heat sink interface and the output air flow is small.The diffusion process has a time constant. It is possible that theimmediate surface of the water film might not be completely saturated ifthe air flow is such that the vaporization time constant cannot besupported by the rest of the thermal circuit.

FIG. (2), FIG. (2 a), FIG. (2 b) show the physical relationship betweenthe fins, the water film, boundary layer and the effect of air flowvelocity. In FIG. (2, 10 is the fin structure at a distance of qfin fromeach other. 12 is the water film and 16 is the boundary layer region. 14is the midpoint of the fin separation. q(0) is the saturated vaporpressure heat flux flow at the interface of the water film and start ofthe boundary layer. qin(x) shows how the heat flux along x distance fromthe fin in the boundary layer. Together with qout(x) and qflow(x) arethe variation of the heat flux at x when the air flow removes the heatflux qflow(x). The laminar velocity profile of the air flow which has amaximum velocity Vmax is shown in FIG. 2 a. Note that the velocity closeto the water film is small and the vapor gradient is very high. Thetotal of qflow(x) over the boundary layer is under continuous heat fluxflow equal to q(0). In FIG. 2 a 18 shows the condition and the width ofthe boundary layer 16 for a volume rate of air flow. 20 is airflow thatis adjusted lower than on 18. Note the reduction in the boundary layerthickness with higher air velocity 18. When the cooling load increasessuch that q(0) increases, 18 changes closer to the profile 20. Thus formuch larger loads where the boundary layer increases towards the centerof the fin separation, there is the necessity to increase the air flow.The boundary layer has the limit for a vapor pressure profile where themiddle of the fin spacing is such that the vapor pressure therecorresponds to the saturated vapor pressure for the ambient airtemperature. If more flux has to be maintained then the heat flux willmanifest itself in the material as sensible temperature across theboundary layer. One can say therefore that the maximum temperaturechange across the vapor boundary layer would have a profile where theheat flux that is needed to be carried together with the air flowrelative humidity and velocity would result in a saturated conditionacross the whole boundary layer. Otherwise beyond that air flowtransport mechanism would involve sensible heat process which wouldincrease the air flow temperature. To sustain the heat flux of q(0), theairflow over the boundary layer should extract the total of q(0).

FIG. (1) and also FIG. (3) shows the increase in the saturated watervapor capacity of air with temperature. The equation came from the NOAAbranch of the federal government. FIG. (1) also shows the remainingwater vapor that can be contained with the same volume when air has therelative humidity of 40%. FIG. (3) shows the comparison of saturatedwater vapor and relative humidities of 40% and 75%. The other curveshows the effect of heating the ambient air when it is low (68 F) to ahigher temperature to open up more capability for air to absorb watervapor. Heating has to be performed without undue acquisition of watervapor.

The criteria above on sensing the inception of sensible heat mechanismin the boundary layer as the increase of air flow temperature will beused for a sensing mechanism to generate feedback signal for the waterdelivery controller to optimize the contribution of the transportmechanism using vaporization.

FIG. 2 a assumes that the relative humidity of the incoming air isconstant. If the relative humidity gets lower, then the boundary layergradient profile will be steeper. This means that the cooling capacitywould be higher because it will take more heat flux to bring theboundary layer edge to the midpoint of the fins. Note that when there isno air flow, the development of the diffusion vapor pressure gradient isthat in steady state, the space between the fins would acquire the sametemperature as the source of heat. On the other hand, it is possiblethat the temperature of the water film interface vapor is at a lowersaturation because of the time constant for vaporization and attendantdiffusion process.

The practical air flow velocities under the aesthetic and powerconstraints are usually such that it would be laminar. The laminarprofile of air flow is characteristic of the velocity at the immediateheat source surface is almost zero increasing at parabolic rate to itsmaximum at half the distance of fins. Since this is the highestconcentration of the water vapor, then a little higher air flow thanwhat would calculate to have an effective mass flow transfer is needed.Nevertheless because of the large energy for vaporization, the amount ofair necessary to convey the water vapor is less. Since the boundarylayer could be designed with the airflow control to be thin, then theeffective “thermal resistance” of the boundary layer is minimal. Thecontribution of heat flux flow because of the thermal resistance isnegligible compared to the heat flux because of the transport of thecreated water vapor. This means that the “temperature head” on theboundary layer in the air medium for convection is significantly higherthan the resulting “temperature head” with the water vapor as atransport material for convection. The resulting improvement on the“temperature head” allows lowering the temperature at the computer chipand increases its reliability.

Examples of Natural Vaporization and Other Applications on CoolingEquipments Using Vaporization

The following are manifestations of vaporization in both the naturalenvironment and also in some cooling practices. We shall discuss them toemphasize the differences and point the main factors affecting theefficiency of the processes.

The flow of heat flux is a circuit where the heat source, usually at ahigher temperature generates diffusion to transport heat from the sourcedown the thermal circuit. The magnitude of the heat flux would bedependent on the resistance presented by the materials along the circuitto the flow. This is called the thermal resistance of the material. Itis a physical characteristic of the material and also dependent on thetopology. There could be several materials involved along the thermalcircuit before the heat flux is conveyed to the water film as shown inFIG. (8). Thermal efficiency using the water for vaporization is tomaintain the capability to support the vaporization from the water filmby sufficient heat flux flow.

The process of vaporization is when liquid water changes from a liquidstate to a vapor state and is called either transpiration orevaporation. The term is mostly correlated with the system. Vegetationvaporization which is one of the main contributors to our weather isusually called transpiration. The term could be applied to processeswhere the water source is introduced to the vaporization process throughsmall pores or channels from other materials.

It is my opinion that the difference is whether the liquid water isintroduced to acquire the energy from some controlled enclosure oravailable in open environment. For our purposes here I will notdistinguish the terms and use vaporization.

Transpiration is the term used on vaporization in vegetation, FIG. (4)shows a schematic on the vaporization. The energy from the sun 44maintains the temperature on the surface of the leaves and around theimmediate area of the leaves. These are balanced by the naturalproperties of color, stomata reactions, wind to achieve an energybalance. The water from the roots rises up by capillary action throughtubes 46 to the leaf structure and exposed to the atmosphere by theopening of the stomata pores on the leaves. The water within the leaveschamber has established saturated vapor pressure. When the stomata 42opens, the leaf opening chambers 40 are exposed to the lowerconcentration of water vapor in the immediate surface of the leaves andenables vaporization. The vaporization process is controlled by thevegetative plants in response to its need. The response of the leaves isdependent on the available energy from the sun and also the transportmechanism on the resulting boundary layer by wind action. Thevaporization process effectively reduces the temperature of the airaround the general area of the tree or vegetation. The transpirationprocess allows the vegetation to undergo photosynthesis with theattendant transformation of sun's energy into the vegetative materialsfrom which we get our food, air to breathe and among others control ourweather. It needs to be pointed out that the temperature inside the leafwhere the saturated vapor barrier is generated before the stomata openscould be at a lower temperature than the ambient air. This is trueprovided the vapor pressure of the ambient air is lower than thesaturated vapor barrier when the stomata opens. This is magnified whenwind blows to carry the vapor materials out and lowers the boundarylayer thickness. In nature, the requirement for vegetation for themagnitude of vaporization is small (typically 0.7 grams/day),

The energy from the sun 50 is absorbed by the water body in open areas.FIG. (5) shows the sketch of the vaporization for open surface or water.Some molecules of water have more energy and able to escape and form avapor barrier above the surface. There is also at the same time energyextracted from the air above the water surface qair but because of therelatively larger thermal resistance to the air, most of thevaporization energy qflux is taken from the water. The vaporizationprocess continues to steady state conditions depending on the effective“thermal resistance” on the boundary layer. The boundary layer ismaintained such that a continuous vapor qflux is sustained. This is thelimiting rate by which vaporization occurs. The vapor pressure gradientof this layer could be altered by wind motion above the surface and thevariation in temperature of the air. In most cases the heat ofvaporization is manifested with small amount of sensible heattemperature changes but mainly by vaporization that is aidedconsiderably by the vapor transport with wind action.

Evaporative coolers or swamp coolers shown in FIG. (6), These areeconomical and effective cooling equipments especially in low humidityand high temperature environments, The block diagram of the equipment isshown in FIG. (6). 50 is a fan enough to provide sufficient air flowthrough a porous mesh usually made of fibrous tree material 52 thatallows distribution of water uniformly on the pad. The air from theblower 50 serves both as the boundary layer that forms when the fanchanges the water into mist. Also it might carry some particles of waterto the ambient environment where the velocity of the water droplets hasthe eventual falling and route exposed to the environment for theextraction of the material around the boundary layer of the droplets.Notice that the effective thermal conduction at the boundary layer isnot consistent. The movement of the spray drop from the equipmentprovides the air flow discussed above to create a low thermalconductivity. The velocity of the water drop as it is generated by themisting process effectively provides the convection to remove the watervapor on the water drop surface. Also the relative humidity of the airincreases and affects the effectiveness of vaporization because of theattendant increase in relative humidity. The increase in water vapor inthe area affects the comfort level in spite of the reduction of thetemperature. The efficiency is low because it is hard to control anddirect air flow to be able to create the complete vaporization of thewater mist. This leads to high water usage and also energy for the fan.Nevertheless under environments stated above of high temperature and lowhumidity, the economic benefits and added comfort levels overcome anyefficiency issues. The effectiveness of these devices are dependent onlow relative humidity environments that is capable of absorbing largeamount of vapor for cooling without affecting the relative humidity andcomfort zone in the area.

FIG. (7) is the sketch for water tower cooling. The heat exchanger 54 isa water tank surrounding the labyrinth of pipes containing therefrigerant circulating through pipe 66. The slow water flow togetherwith the relatively high thermal conductivity of the water intimately incontact with the refrigerant enclosure walls enables relativelyefficient heat flux transfer. The heat from the refrigerant is routed tothe water tower with the transfer pump 56. The warm water is sent to asystem that drops the water from 58 into skids or crates 60 thatmechanically present the water to the high velocity air from the fan 62.Water from the skids and crates form water fall of droplets fallingagain the air fan blown air. The droplets have the vapor barrier aroundand these are exposed for removal with the relative motion of the airflow from the fan 62 and the fall with gravity.

The system is an effective cooling system that has drawbacks onoptimizing the potential of vaporization. The heat flux has to beconveyed from the refrigerant to the refrigerant enclosure. From theenclosure the next thermal component is the transfer from the enclosureto the water. The transfer is improved because of the velocity of thewater across the enclosure tubes carrying the refrigerant The flow ofwater is routed to water skid crates that creates films of water to theair flow from either an air flow fan above or below the water coolingtower. The efficiency of the implementation is dependent on the flow ofheat from the refrigerant to the water for vaporization. The presentmechanization for taking advantage of the large latent heat of phasechange for water is not optimized. There are a number of materials fromthe refrigerant to the introduction of the water film for vaporization.This lowers the available saturated vapor pressure on the water film.The thermal circuit consisting of the following accumulates andincreases the thermal resistance from the refrigerant to thepresentation of the water for vaporization. The heat flux flow and theresulting temperature drop is significant. Thus at the transition wherethe liquid water is presented for vaporization, the effective vaporpressure which is dependent on the temperature has decreased from thetemperature of the refrigerant. Also there is a net result of wasted airflow energy because the air flow is not focused on the boundary layers.The effectiveness of concentrating the fan energy to carry as much ofthe vaporized material as possible is not optimal Another practicalissue is that since the usual manner of water delivery exposes thematerial to ambient air especially at the water tray 64 results in theaccumulation and increase in bio film enabling materials and organisms.Bio film scaling is product of interaction of bio components with thewater to cling in an ionic manner to the metal surface. This is affectedbecause of the high temperature at the surface together with the lowwater flow velocity giving the ionic process time to be effective. Biofilm buildup is usually the precursor to the formation of permanentadhesive materials for further scaling from other sources likecarbonates from the water. The initial bio film serves as initial anchorfor the carbonates and has the property that after a certain thresholdin time, the permanency of the adhesion to the metal surface increasesexponentially. This leads to the acceleration of degradation of thethermal conductivity of the transfer of heat from the refrigerant to thewater medium. Expensive total downtime for maintenance of the systemtherefore is an economic and logistic issue.

DETAILED DESCRIPTION

The process in this application consists of several procedures that isto maximize the tremendous cooling capacity of vaporization when used asa transport medium for convection. FIG. (8) represents a general thermalcircuit in terms of possible topology for the heat flux path forpresentation to the water film for vaporization. The thermal circuitshown could represent the various topologies possible in the creation ofa flux path for the heat flow from 80 the refrigerant to the ambientenvironment 78. The different contributors to the thermal circuit areshown to be 82 as a series component, 70, 72, 74 as parallel componentsconfigured to form an equivalent component, 84 as another seriescomponent. 74, 88, 86 is a general representation on how the water filmmaybe introduced to enable vaporization. 88 could be eliminated. It isshown here to represent a water delivery topology where the waterchamber 76 acquires the heat energy from the previous materials andcreates the water film on the other side of 88 if 88 is a porousmaterial that has microchannels that allow water to move from 76 to thewater film area 86. This type of topology is used for example in watercooling jars prevalent in South East Asia and also presented as apossible embodiment in the computer chip cooling. The different materialmedium that are in “series” or “parallel” are indicated. The mainobjective is to minimize the accumulation of material contributions tothe net thermal resistance from the source to the water film. Theprocedure of optimizing the thermal conductivity of the usual metalcontainer or transfer material to maximize the heat flux is very wellknown and understood. The thermal conductivity of metal, e.g. copper is400 while the thermal conductivity of water is 0.6 watts/m/sec. One cansee that assuming the areas involved are the same, the ratio of thethickness of the copper to the water film would be 666:1 (400/0.6) forboth to exhibit the same thermal resistance. Thus water film thicknessof 1 mm would have the same thermal resistance as copper with thicknessof 66.6 centimeters. The process therefore would require that the waterbe delivered to the warm surfaces such that the effective water film isas thin as possible. Vaporization with convection results in minimaltemperature change within the boundary layer.

Metering of the amount of water delivered so that only the requiredcooling requirement is delivered would use the measurement of thetemperature rise from the incoming air flow for the condenser fins tothe outgoing air flow temperature. Since the process of vaporizationwith convection results in minimal temperature change (mainly toestablish the boundary layer gradient), then metering could beimplemented as a feedback control system where the water delivery isenabled only when the output air flow temperature is very close to acertain threshold to the incoming air flow temperature. The threshold asa control parameter indicates the approach of the air flow to vaporsaturation with the start of the sensible heat transfer. The value ofthe threshold is a subjective decision for the designer or user. Itcould be before or after the inception of sensing the saturation of theair. The magnitude and effectiveness of vaporization is both affected bythe water delivery and the transport mechanism of convection. Inupgrades, since the fan has a fixed speed, then the remaining controlparameter is the water delivery rate.

FIG. 9 shows the general structure of the cooling equipment. Thetemperature of the incoming air is measured with sensor 90 and thetemperature of the outgoing air is detected by an identical sensor 92.Direction of air flow is shown by the arrow bands. FIG. 9 a shows thepossible arrangement of the sensor so that an average function of thetemperature within the air flow area is measured in an averagingprocess. 90 and 92 are coils made of a very controlled length anddiameter wire routed around as shown in FIG. 9 a. The routing wouldfollow the consecutive numbers and their position. There could be someother more practical implementation but there it is preferred to havesome averaging capability. If there is assurance that there could be nophysical elements affecting location of single point temperaturesensors, then the average can be done with an electronic filter circuitor in the case of embedded controllers as a digital filter. Since thewires of the coils 90 and 92 are identical then their resistance areidentical at the same temperature. FIG. (10) is an implementation of apossible circuit block diagram to perform the feedback mechanism formaintaining the closeness of the two temperatures sensed by 90 and 92.102 and 102 are very accurately controlled current sources that providesconstant current under all conditions to the temperature sensors 90 and92 that are exposed to the area for the input and output air flow. Ifthere is a difference in temperature measured by 90 and 92 then thedifferential amplifier 110 measures and amplifies the difference. It issent to the controller circuit 112 which could be implemented in variousmanners. For example, it could be a similar circuit to a switch modeforming signal. The energy for the driver would be in the form of asignal that is repeated at a certain frequency adequate to support themaximum drive needed. The duration of time during each initiation ofpower is controlled and called the duty cycle. Modulating the duty cyclewould control the amount of energy flow to the motor driver 114. Theduty cycle and the frequency generate the necessary signals to drive theperistaltic pump motor 116 for either clockwise or counterclockwiserotation. The peristaltic pump motor 116 is with the water tank for thewater delivery metering process.

There is an added benefit to the metering of precise water requirementfor cooling because it automatically retards the occurrence of bio filmscaling buildup on the metal surfaces. In ordinary heat exchangers, biofilm buildup occurs because of the presence relatively slow velocitycontinuous water around the metal surfaces. The slow moving water withthe high temperature result in the formation of bio films on the surfaceof the metal. These present themselves as anchoring points also for theaccumulation of carbonate deposits. The combination leads to expensivemaintenance of cooling systems. The metering of the water avoids thepresence of continued liquid water that enables the formation of biofilm. The metering also enables prediction of the magnitude of carbonatescaling buildup with knowledge of the hardness of the water. This wouldresult in a logistical maintenance strategy since the extent ofdegradation of thermal conductivity is predictable to the level that theeconomic benefits could be maximized.

The other aspect pointed by the process is that the vapor barriergradient in the boundary layer has to be optimized such that the heatflux is maintained at the maximum where the initial vapor pressure atthe immediate water film boundary. The high vapor gradient should bemaintained by the effective removal of the water vapor. This involvesadjusting the air flow such that with the laminar flow it is sufficientto carry most of the material within the quadratic profile inherent withlaminar flow. It is desirable therefore that the chamber for the airpassage have minimum thickness. This however could lead to highervelocity and more noise. There are some cases where the topology of thepresentation of the water film to the air flow is such that turbulencealong the length of the air motion is possible. This would be effectivein getting the vapor barrier gradient very steep and improve diffusionmechanism.

FIG. (1) shows that the amount of saturated water vapor at lowtemperature is relatively small. The cooling capability is limited atlow ambient temperatures because of the available water vapor capacityof the air. When the magnitude of cooling required is large the need forhigh heat flux then the needed higher water vapor is limited by theambient air temperature. In the case of the air conditioners, thetemperature of the refrigerant on the condenser is high. The ambienttemperature of the air when the air conditioner is needed is usually ata temperature where there is adequate room for the air to accommodatethe needed vaporization for cooling. Therefore, the normal ambienttemperature for condensers operations in air conditioners allowvaporization to work effectively for the power level and the presenttopology of the condenser fins and tubes. The condensers used forrefrigeration however would operate under lower ambient temperatures.The limited volume of water vapor that could be supported by air at thelow temperature for high cooling loads are degraded. Notice that thevaporization process is such that the heat source temperature will bealmost the same as the ambient temperature air flow because of the lowthermal gradient of the boundary layer. This means that if vaporizationof applied to the level that it is the complete process for cooling thecondenser, then the condenser refrigerant temperature is almost veryclose to the temperature head between the refrigerant and the enclosure.The limited water vapor capacity at lower temperature could be increasedby raising the resulting temperature head higher than the idealmentioned. The temperature is almost close to the temperature head ofthe refrigerant to the enclosure. Under this situation, the immediatecompensation is to adjust air flow volume rate. This could lead tohigher noise level and demand from the fan. However with upgrades, airflow adjustments are not available. FIG. (3) show that warming up theincoming air flow temperature would raise the capability of the air tosustain and support the higher vapor pressure product needed for thecooling.

The heating process for the incoming air flow could be done severalways.

One way would be to use the actual condenser cooling process to beadjusted such that sections of the condenser would operate the usualconvective process with air as the transport material. The output airflow from that section of the condenser with the increase in sensibleheat is used for the air flow need on the section of the condenser thatwill utilize the vaporization process. Since the sensible convectiondoes not affect the amount of water vapor, the output would have lowerrelative humidity at the raised temperature. For example, in airconditioner condensers, part of the fins and tube system modified in anarrangement where the incoming ambient air does not make use ofvaporization and stays on the sensible region for heat exchange. Theheat is absorbed by the air and is manifested as an increase intemperature. The output air can now be routed mechanically to the othersections of the condenser where vaporization cooling mechanism isimplemented.

When the air flow through 110 fins, it has an increase in temperaturebecause the transport mechanism is air and would have an increase insensible temperature. This output air flow is now used for 112 sectionof the condenser where the vaporization procedure is applied with thewater delivery implemented through the valve 114.

Another process would be to preheat the air with controllable powersource.

Another would be to use hybrid of the two methods to obtain theflexibility that might be required in some systems. The procedure isdiscussed in the third embodiment.

DETAILED DRAWINGS

FIG. (1) Graph of saturated air of temperature F

FIG. (2) FIG. (2 a), FIG. (2 b Heat flux and air flow at the boundarylayer

FIG. (3) Graph of saturated air and emphasis of warm air allowing morecooling capability

FIG. (4) Sketch of transpiration in vegetation

FIG. (5) Sketch of evaporation in open water

FIG. (6) Sketch of vaporization in swamp coolers and evaporative coolers

FIG. (7) Sketch of vaporization in water tower coolers

FIG. (8) Sketch of general material path for heat flux to the water filmfor vaporization

FIG. (9) Diagram of location air flow sensor

FIG. (9 a) Sketch showing averaging with topology of construction oftemperature sensor

FIG. (10) Block diagram of water metering control circuit usingtemperature sensors and pump

FIG. (11) Block diagram of air pre conditioning by using air flow fromcondenser that uses sensible heat of air for convection transfer

FIG. (12) Sketch of how vaporization is created to show components

FIG. (13) General block diagram of vapor compression and recovery systemof cooling

FIG. (14) Phase diagram for R22 to show operation within saturatedregion

FIG. (14 a) Magnified phase diagram on the compression cycle

FIG. (15) Phase diagram for an actual AC system indicating non idealoperation

FIG. (16) Magnified phase diagram for an actual AC system with pressureand enthalpy

FIG. (17) Phase diagram for an actual AC system with vaporizationprocess applied

FIG. (18) Phase diagram for actual AC with vaporization applied(pressure vs. enthalpy)

FIG. (19) Water delivery block diagram

FIG. (20) Water delivery tray

FIG. (20 a) delivery to implement uniform water droplet distribution

FIG. (21) Block diagram of general implementation of vaporization andpre conditioning on upgrades

FIG. (22) Implementation of upgrade without air pre conditioning

FIG. (23) Implementation of upgrade with air pre conditioning

FIG. (24) Block diagram of upgrade with maximum flexibility on air flowpre heating

FIG. (25) Alternative implementation using spray nozzles as alternativeto water delivery trays and pegs

FIG. (26) Sketch of top view (orthogonal drawing) Computer chip heatsink

FIG. (27) Sketch of front view (orthogonal drawing) Computer chip heatsink

FIG. (28) Sketch cross section of heat sink 1^(st) module (looking down)

FIG. (29) Sketch cross section of heat sink 1^(st) module (middle)

FIG. (30) Sketch cross section of heat sink 1^(st) module (looking up)

FIG. (31) Sketch cross section of heat sink 2^(nd) module (looking down)

FIG. (32) Sketch cross section of heat sink 2^(nd) module (looking up)

FIG. (33) Sketch cross section of heat sink 1^(st) and 2^(nd) module(fins and air flow heating)

FIG. (34) Sketch of water distribution sock arrangement

FIG. (35) Sketch of cell structure creating hierarchical systemorganization

DESCRIPTION FIRST EMBODIMENT

The first embodiment is on improving the efficiency of the condensers onair conditioning or refrigeration equipments. This embodiment inparticular is for the upgrade of existing air conditioning systems.

The government has mandated through the Department of Energy a gradualimprovement on the required efficiency of new air conditioning andrefrigeration equipment following policies similar to the gas mileage oncars. Also the Department of Environment and Protection last January2010 has prohibited particular refrigerants for the new manufacturedequipments. The usual refrigerants on the old systems are the R22. Theinstalled base of these old equipments however are at least 75% of themarket for saturated capacity. Thus if the efficiency of the oldequipments is improved by economically viable process, then the plannedpolicy of energy use for the nation would be accelerated. The known lifeexpectancy of the air conditioning and refrigeration equipments areabout 20 years. Therefore statistically, there is a percentage of 9 moreyears remaining in the life of these units for availing on efficiencyimprovements afforded by this procedure.

The theoretical ideal efficiency of vapor compression refrigerationsystem which are the usual technology used for air conditioners andrefrigeration is the COP or the coefficient of performance. Under someassumptions, particularly that the refrigerant operates within itssaturated boundaries on the different phase used for the purpose, theCOP is obtained as the temperature of the evaporator refrigerant (usingabsolute temperature units such as Kelvin or Rankin) divided by thedifference in temperature of the condenser refrigerant and theevaporator refrigerant temperature. Again using ideal conditions,assuming the condensers and evaporators are considered as infinite heatsinks or sources, then the refrigerant temperatures are either theambient temperature or the control setting for the air conditioners.This is not the case however because of practical inefficiency in theheat transfer process for these equipments. These devices uses theconduction and convection process discussed above using fins and tubesfor the condenser enclosure and surfaces and electric fan for the airflow. The standard design for air flow is 400 cubic feet per minutes ofairflow for each ton of cooling capacity for condensers. Therefore for a3 ton unit and the typical dimensions for the tubes and fins, one cancompute for the “temperature head” to be approximately 18.5 C for thecondenser. I defined the term “temperature head” to be the difference inthe refrigerant temperature between the heat flow source to therecipient heat environment. The Department of Energy defines a standardmetric for efficiency for air conditioners and refrigeration systems.The standard is the SEER or seasonal electrical energy rating. Since theperformance of an air conditioning system is dependent on the ambienttemperature and the room temperature setting, the SEER metric isspecified for ambient temperature of 85 F and room setting temperatureof 82 F. The standard is computed the same as the COP (under the actualequipment performance, and not ideal to operating within the refrigerantsaturated region). The SEER could be obtained from the COP by dividingby 0.29. SEER uses BTU/hr for energy instead of watts for COP. Assumingthat the evaporator coil also has the same “temperature head”, then thetotal difference on the refrigerants of the two devices is approximately37 C. There is approximately 3.5 C temperature head due to the thermalconductivity of the refrigerant together with the usual implementationof the enclosure for the conduit for the refrigerant. We may considerapproximately the same for the evaporator. For the sake of discussion,under the ideal COP computation that the condenser were to use thevaporization method and result in a “temperature head” reduction of 18C, this would imply an improvement of 61%. This theoretical unit wouldhave a COP of 6.73 and reduction of the temperature head of thecondenser by 18 C results with a COP of 10.5.

The new equipments mandated by DOE for efficiency performance would havehigher SEER ratings. If the vaporization process were applied to theseequipments, the resulting efficiency improvement would have a largerrate of improvement. This could be seen by getting the derivative of thetheoretical expression for COP with the condenser temperature headchange. The rate of change is directly proportional to the existing COPor SEER performance.

This application is a method by which the efficiency for the refrigerantheat extraction is improved. The method is applied to the usual fin andtube type of heat exchange by exposing the heated fin and tube of thecondenser to water to induce the vaporization and extract the heat fromthe refrigerant by the usual thermal conduction and convection using airflow. The vaporization of the water is enabled by reducing the thermalresistance from the refrigerant to the receiving medium which is ambientair. The usual structure of the fin and tube is not changed, but theintroduction of water on these surfaces together with the hightemperature of the refrigerant induces the conduction of heat energy tovaporize the water on these surfaces. The vaporization of the water isvery efficient heat transfer mechanism. The latent heat of water is 2260joules if 1 gram of water is vaporized. In comparison the sensible heatchange of the air with the convection and conduction with the standardprocess employed with existing equipments provides only 0.001joules/cubic centimeter/degree celsuis change of the airflow. Thestandard fan requirement followed in industry is approximately 400 CFMper ton of cooling capacity. When water is vaporized from the condenser,the boundary layer consist of water vapor in the immediate surface areaof the fins and tubes that form a similar boundary layer of heated airas with the usual fins and fans arrangement. If the boundary layer ismaintained to a steady state allowed by the diffusion mechanism, thenthe thermal resistant would increase to the point that the heat transferis degraded. The effectiveness of vaporization for cooling capacityimproves if the relative humidity of the air is low together with highertemperature of the air. The saturation level of water vapor content ofair increases exponentially with temperature. Therefore, for the samerelative humidity (which is the ratio of the water vapor content of theair to the saturated water vapor content) at a given temperature, thereis more water vapor that could be absorbed by the airflow at higherambient temperature. In order to optimize the design the air flow volumeis sustained only up to air saturation. With the standard fan capacityof condensers, the 400 CFM volume capacity of the fan is adequate tomaintain the total cooling requirements under all practical ambienttemperature the condenser is allowed to operate.

The air conditioning and the refrigeration technology had beenimplementing the vapor phase change and recovery for cooling for a longtime. The basic components are known and established. The components ofthis cooling system are shown in FIG. (13). The cooling system is aclose system where it uses a medium called the refrigerant that issubjected to changes in its phase as it goes around the cooling system.The change in phase is implemented by means of equipments that aredesigned to enable the flow of energy as required by the laws ofthermodynamics. The phase changes are such that in suitable sections ofthe system heat can either be absorbed or removed from the refrigerant.The equipments involved are situated in the area being cooled (theevaporator) and the area where the heat is dumped to the environment(condenser). The thermodynamic cycle that the refrigerant undergoes isenabled by introducing some form of energy (in this particular blockdiagram, electric compressor) and a metering system. The design andimplementation of the processes by which the phase change of therefrigerant are factors that determine the efficiency of the coolingsystem. Practical constraints on the design stage are however always afactor.

This application is for the improvement of the heat transfer performanceof the condenser. Embodiments to apply both to existing and manufacturednew equipments are presented.

The efficiency metric for the cooling system maybe understood byexamining the thermodynamic cycle of the refrigerant under an idealcondition where the phase transformation of the refrigerant is limitedto the saturated region. FIG. (14) shows the phase diagram for the airconditioning refrigerant. The usual thermodynamic diagram that therefrigerant undergoes can be presented in a combination of ways. Therefrigerant exhibits the same pressure and temperature and are calledthe saturated temperature and pressure of the refrigerant. Therefore,measurement of either parameter will describe completely the state ofthe refrigerant in this saturated phase.

I have to beg forgiveness for the deviation of the usual way ofpresenting the phase diagram. However since in this discussion, we areconcerned about the idea of COP as a function of the operation withinthe saturated region, I believe the choice of the parameters for thephase diagram shown would make the migration to the practical systemmore understandable. The phase diagram is shown as temperature versusenthalpy. The usual choices are pressure against enthalpy, andtemperature against entropy.

On the left of the phase diagram is the boundary of liquid and mixedstate (liquid and vapor coexist) for the refrigerant. On the right isthe boundary of changing from the mixed liquid and vapor (saturatedregion) to a completely vapor phase. The independent (horizontal axis)variable is shown as the energy content of the refrigerant per gram thatflows through the evaporator or condenser devices. The energy increaseor decrease of the refrigerant as it traverses along the cycle isindicated by the enthalpy H. The enthalpy change H is dependent on theentropy S of the refrigerant. The entropy changes with the correspondingchanges in energy flow in or out of the refrigerant. The enthalpy changeis manifested as the temperature (absolute) T multiplied by the changein entropy along the cycle. The accumulation of the changes in energycontent of the refrigerant are shown at the indicated transition pointsas the resulting energy per gram of refrigerant. During the phase changewithin the saturation region, both the temperature and the pressure areconstant, e.g. from (1,2) to (2,3). Since the temperature is constant,the changes in enthalpy are all related to the absolute temperature andthe effective change in entropy. Outside of the saturated region ofoperation the temperature and pressure change with corresponding changesin entropy. One can see now why it is a rational strategy to assumeoperation of the vapor compression recovery system to occur only forpurposes of deciding strategies for efficiency improvement with theunderstanding that this region of operation contributes to most of theenergy involved with the metric of efficiency.

The mechanical losses with the movement of the refrigerant through thetubes could amount to a significant loss in energy and thus efficiency.For example if the pressure drop through the evaporator results in asaturated temperature change of 3 C, this is approximately 1 percent onthe cooling capacity of the evaporator. Other factors are ignored. Forexample the mixed presence of liquid and vapor in the tubes createsmechanical states of blobs of empty spaces or sections of completelyliquid refrigerant or vapor along the tube. Another are the losses inthe throttling process where some of the energy during thetransformation from the liquid output of the condenser to the lowertemperature results in a phenomena called flashing where vapor iscreated with the throttling process resulting in loss of energy. Sufficeit to say that it is mentioned here but the impact of theircontributions to the losses are ignored.

The solid line depicts the boundaries by which the phase of therefrigerants changes to being completely liquid or vapor to acombination of liquid and vapor when the refrigerants acquires heat. Theright side of the phase diagram shows the boundary by which therefrigerant phase changes from the saturated phase (combination ofliquid and vapor) to a completely vapor state. This is the region asshown in FIG. 2 with labels (1,8) to (2,3) and also ((4,5) and (6,7).The points indicated from 1 to 8 marks where the different cycles of therefrigeration cycle change. (1) and (8) is when the refrigerant entersthe evaporator where warm air energy from the room is extracted by therefrigerant. The regions between (4,5) and (6,7) is the condenser wherethe energy extracted from the evaporator is rejected from the system tothe outside environment. Thus the refrigeration system extracts heatfrom the room and dumps it out to the environment. When the airconditioning or refrigerant system operates entirely within thesaturated region, the resulting COP or coefficient of performance of thesystem provides the metric a's the ideal limit of the efficiency of thesystem for the phase operation the refrigerant. The COP is a measure ofhow much energy is needed to change the thermodynamic phase of therefrigerant to function from absorbing heat energy and rejecting heatenergy from its' mass. The COP is the amount of energy needed to convertthe refrigerant from (1) to (2) for the mass refrigerant flow divided bythe energy needed for the compressor to change the vapor refrigerantfrom a low temperature saturated phase (2) to a high temperaturesaturated phase (4). The change in energy in the process of eitherextracting heat from the room or eliminating the energy from therefrigerant is shown in the horizontal axis as enthalpy. For example asthe evaporator refrigerant absorbs heat from the room, it's enthalpyincreases from (1) to (2). Since the temperature and pressure of therefrigerant remain constant within the saturated region, then we can saythat the COP maybe expressed in terms of the temperatures. This formulais directly dependent on the low side temperature (evaporator) of thesystem and inversely proportional to the difference in the temperaturebetween the high side (4,5) to (6,7) (condenser) and the low side (8,1)to (2,3) (evaporator) saturated refrigerant temperature. The temperatureshould be consistently in absolute Rankin or Kelvin units. The low sidetemperature of the refrigerant is dictated by the setting desired forthe system. For an air conditioning system, this would be a temperaturefor human comfort. For a refrigeration system this would be dependent onthe purpose for the refrigeration. For a freezer, the low temperaturewould be below freezing temperature of water. Thus, the theoreticallimit of performance for this particular cooling system is bounded bythe two temperature requirements, namely product usage and the ambienttemperature. If the condenser and evaporator are infinitely efficient inheat transfer, then the area of concern would be its minimum. This meansthat the denominator on the COP formula is reduced and would result in ahigher COP. The high side refrigerant would be close to the ambienttemperature, and the evaporator low side refrigerant temperature wouldbe close to the control room temperature. In reality, the ideal infiniteheat transfer is not achieved because of the thermal resistance inconveying the heat flux from the refrigerant as required for thefunction of the evaporator or condenser. I will use the term“temperature head” as a metric for the magnitude of the average thermalresistance of the evaporator or the condenser with respect to eitherambient temperature or the room control temperature. The “temperaturehead” is the difference between the condenser and evaporator ambient androom temperature and the corresponding refrigerant saturatedtemperatures. The temperature head are determined by the physicalimplementation for each of the units. There are other losses that addsto inefficiency in the implementation of a physical system. These aresuperheating, sub cooling, flashing, mechanical losses, hydraulic losseson the plumbing and electrical efficiency losses on the motors for thecompressors and fans. FIG. (15) shows all these other thermodynamicprocesses involved with a practical refrigeration or air conditioningsystem.

The COP metric disregards all these factors but serves as a guide toachieve higher efficiency for the cooling system. The term superheatingresults from requiring practical air conditioning systems to haveadequate assurance that the refrigerant to the compressor at the suctionline are all in vapor phase. Otherwise the compressor could be ruined.The term sub cooling is similar to superheating except it is the degreeby which the refrigerant from the condenser is cooled lower than thesaturated temperature of the refrigerant. Flashing is when the energy ofthe liquid during throttling converts some to vapor with the attendantloss in energy. We neglect inefficiency on energy based on the relativetotal energy contributions compared to the thermodynamic processeswithin the saturated regions.

Note for trivia that under the specifications of the ambient temperatureand control temperature set for the definition of SEER, thecorresponding COP under ideal condition of infinitely capable heat sinksand heat source for the evaporator and condenser respectively that theCOP is 180 with a corresponding SEER of 622. It is a very far target toachieve but hopefully could serve as encouragement that indicates thereis a lot of room for improvement over the horizon.

FIG. (13) shows the transition points where the VCRS process within theclose loop cycle. FIG. (13) transition points pairs to indicate that arepractical necessities for an actual unit where further processes have tobe implemented. The sequence of the transition follows an increasingorder with the system cycle following a counterclockwise direction.Point (1) is when the refrigerant enters the evaporator as a combinationof liquid and vapor after undergoing “throttling” where the refrigerantpressure is changed from the high saturated pressure (8) to the lowersaturated pressure and temperature (1). This refrigerant phase enablesthe extraction of heat from the room because the saturated temperatureof the refrigerant is lower than the room temperature setting. When theheat from the room is extracted in reaching (2), the refrigerantundergoes mechanical work. This transition point in FIG. (10) also showstransition (3). This is to show that in an actual cooling system, it ismandatory to operate the cooling system such that there is assurancethat the refrigerant is completely in the vapor phase before undergoingmechanical work by the compressor. Otherwise, the presence of liquid inthe refrigerant could ruin the compressor. From (3), the compressorchanges the pressure and temperature of the refrigerant by introducingwork. This raises the temperature and pressure of the refrigerant to(4,5) in FIG. (14). Transition point (4) is the state of the refrigerantafter the compressor. FIG. (15) shows the full phase change cycle forthe refrigerant for an actual system tested with R22 refrigerant. Thecompression of the refrigerant is not in the saturated region (4,5) to(6,7) because of the reason on maintaining complete vapor on the inputto the compressor. FIG. (13) disregards this in order to simplify theexplanation on how to achieve thermodynamic efficiency. Cooling of therefrigerant brings it to the saturated region (5). The transitionregions (4,5) to (6,7) is when the condenser rejects it's heat contentto the ambient environment. Therefore the energy used for cooling theroom would be the changed in the enthalpy (horizontal axis) fromtransition point (1) to transition point (3). The condenser on the otherhand removes the energy corresponding to the difference in enthalpy attransition point (4) to transition point (8). The work provided by thecompressor would be the enthalpy change from transition point (3) to(4). Examination of the phase diagram FIG. 2 shows that the magnitude ofthe change in enthalpy over the regions where the refrigerant is in thesaturated region is much larger than the region where the work involvedin achieving the change in phase of the refrigerant by the compressor.The other losses such as pressure drop loss on the tubing for theevaporator and condenser affects the thermodynamic efficiency in asignificant manner because the horizontal track (1,2) in the evaporatorand the horizontal track ((5,6) drops from being horizontal. The effectis to reduce the average effectiveness of the saturated temperature ofthe refrigerant

FIG. (15) shows the phase diagram that an actual air conditioning systemundergoes. The FIG. (16) in a similar fashion as FIG. (14) are shown toscale such that the magnitude of the energy of the refrigerant isindicated graphically. The saturated regions (1,2) and (5,6) have energychanges relatively larger than the energy changes on the refrigerantsduring (2,3), (3,4) and (4,5) and (6,7). The region (2,3) is to assurethat the refrigerant enters the compressor to be completely vapor. Thisis termed “superheating” at the suction line. (3,4) is the compressioncycle of the refrigerant. The resulting phase at (4) is both a result ofthe superheating and also the compression process. The region (4,5)cools the refrigerant to bring it to the saturated region. Note that atthe states (4,5) and (2,3) the saturated pressure of the refrigerantsare maintained to be almost the same as the saturated temperatures at(1) and (4). At (5), the refrigerant is completely liquid. When thecondenser has more cooling capability, then the liquid refrigerant iscooled to (7) with the pressure still maintain as from transition point(4) to (7). This region is called the sub cooling of the refrigerant.This is desired similar to super heating the throttling process for amore desirable liquid state of the refrigerant before throttling. FromFIG. 17, which is an actual phase diagram of an air conditioning systemusing R22, one can see that the amount of energy involved within thesaturated regions are much larger than the other phases of therefrigeration cycle. All the figures shown from FIG. (13) were drawn toscale such that the image seen would show the relative magnitudes of theenergy changes through the different transition points.

FIG. (14) through FIG. (18) are all drawn to scale as a result ofanalysis using the R22 refrigerant. One may verify for example in FIG.(14) that the ideal COP definition is satisfied under the condition thatthe refrigerant operates within the saturated boundaries of the phasediagram.

The reduction of the “temperature head” on the condenser is addressed.Particular application is on the process of upgrading older installedair conditioning systems which have efficiencies that are much lowerthan the requirements for system efficiency for new equipments asmandated by the Department of Energy.

This application uses the vaporization of water as a vehicle to conductthe heat flux from the refrigerant in the condenser to the ambientenvironment to improve the cooling performance and capacity of thecondenser.

The process consist of—(1) water delivery metering (2) air flow volumerate control (3) air flow temperature and humidity conditioning. Theseprocesses results in improvement in efficiency over a wider range oftemperature and relative humidity. Also the effect of scaling buildup isreduced with predictable maintenance requirements.

The vaporization process occurs at any temperature. It is the result ofthe equilibrium between the high energy molecules from the liquidbalanced by an equal amount of vapor molecules losing energy andchanging back to liquid. When the enclosure does not loss any of thematerial water vapor, then the equilibrium state is called thesaturation level at that given temperature. The saturation level isexponentially related to temperature. The saturation level implies thatit creates a vapor pressure because of the high concentration of watervapor. The vapor pressure is dependent on the temperature. Diffusiontherefore starts together with a negligible amount of sensibletemperature change perpendicular and away from the water film. Diffusioncreates a water vapor profile and temperature profile toward the steadystate where the whole chamber would acquire saturated conditions Afterthis, the heat flux flow stops. An upper limit on the gradient of thevapor boundary layer is dependent on the saturated water vapor contentas it traverses away from the water film surface. Thus theoretically,the temperature of the water film could be made to be close to theambient environment. The temperature gradient could be made very sharpby ensuring that the vapor pressure from the surface of the water filmis as high as possible. This would be adequate if the air flow caneffectively keep up with the generation of water vapor and establish avery sharp gradient for diffusion. The process of air carrying the watervapor is the mechanism that enables this. As a best case scenario, forexample under the condition that the air flow is adequate in removingthe water vapor created by the vaporization, that the thermal resistancefor the heat flow from the refrigerant energy is limited by therefrigerant and the water film effective thermal conductivity. Thethermal conductivity of the copper or metal tube is so much greater thanthe refrigerant or the water film.

The following factors are design parameters for the effectiveapplication of vaporization for the upgrade. The first is to meter thedelivery of water to the fins and fans such that the needed amount forthe vaporization contribution is maintained. This improves the use ofwater for the cooling process. Also careful metering of the amount ofwater minimizes the thickness of the water film on the surface of thefins and tubes. Thus the contribution of the water film to the totalthermal resistance from the refrigerant to the ambient environment isminimized. This is particularly clear because the thermal conductivityof water is very close to the refrigerant. The second is to maintain theminimum thermal resistance presented by the boundary layer bycontrolling the air flow. The metric for this is the difference intemperature from the ambient air and the exhaust air from the condenser.In the case of the cooling that is applied using the sensible heattransfer of the airflow, the change in temperature is proportional tothe heat energy extracted per unit time for a fixed topological coolingstructure. With the combination of the two heat transfer processes, thelatent heat of vaporization mechanism tends to decrease thisdifferential in proportion to the percentage of cooling attributed tosensible heat transfer. If the latent heat of vaporization of water wereto be optimized, the cooling effect would reduce the sensibletemperature change. Thus the difference in inlet and outlet air flowtemperature is used as a feedback control for the efficiency in thedelivery of the optimum amount of water. The limits would be dependenton the relative humidity of the ambient air since the amount of watervapor that can be generated from the heat transfer would be limitedtheoretically by the saturated air. The normal temperature range ofhumidity and the temperature operation for existing equipments howeverhave SOP equipment performance that saturation is not reached. Thesecond metric is to have a strategy of maintaining the coolingefficiency of vaporization by maintaining the high conductivity of theinterface between the fins and tubes to the ambient air. This ismaintained by minimizing the water vapor boundary layer thickness andalso the conductivity between the refrigerant to the immediate surfaceof the boundary layer. The boundary layer explanation is a catch allexplanation of why air flow is needed. The control of the air flow isneeded to avoid getting close to the boundary of saturation for theoutlet air. The control of these parameters has to be combined andcoordinated with the water delivery system. Analysis applying theassumption that laminar flow occurs on the installed AC fin and tubecondensers shows the validity of the adequacy of the fan installed inthese equipments that are candidates for upgrade. The standardoperational design for these condensers has been 400 CFM per ton of ACcapacity.

The use of water always presents practical problems of scaling. Thescaling problems are addressed knowing the following information abouttheir formation and development. The PH factor is an indication of thepossible magnitude of the potential of the problem. A more acidic waterwould minimize the probability. The interface to the water film wherethe amount of carbonate material that would potentially develop toscaling is contained by minimizing the volume of the water involved. Theamount of carbonates that end up deposited on the metal surfaces arepredictable. This is because the metering process of the water achievesthe total vaporization of the delivered water and all the carbonates areprecipitated and deposited on the surfaces. The amount of deposit wouldbe dependent on the hardness of the water and the total accumulatedcooling energy. The metering of water for vaporization optimizes the useof water and extend the time for which maintenance due to formation ofscaling would be needed. The maintenance could be divided into twosegments. The first segment is the actual delivery equipment to the finsand tube of the condenser. The second segment would be the scaling onthe fins and tubes themselves. The latter would lend to mechanicalcleaning since in most cases access to the fins and tubes are availablebecause of the inherent topology of the present condensing devices. Thusmechanical cleaning with high volume and low pressure cleaning water, isa convenient and economical process. The water delivery material isselected for high contact angle which is a measure of the adhesiveproperty of water to the surface. Maximizing the contact angle for thematerial would reduce the formation of scaling on the material.

The water delivery system is designed such that the metered andcontrolled manner of delivery of the water shall be distributed evenlyon the fins and fans. This would help extend the time necessary formaintenance because it avoids the localization of water distributionflow which accelerates the build up on these local regions. Also it isknown that the scaling that forms has the property that the adhesiondevelops stronger after a certain threshold of time and from that pointon accelerates the build up and formation on this initial scaling toaggravate the conductivity of the device. This property however might bevery dependent on the action of bio film buildup and would have minimalimpact. This is true when the amount of water is sufficient that biofilm maintain on the heated surfaces. This development of bio filmaccelerates the scale buildup due to carbonates. Therefore the strategyis to allow periodically a mechanical cleaning of the surfaces of thewater delivery. It is proposed to flood the water delivery from anothervessel and then while it is flooded subject the container to mechanicalpressure forces in terms of ultrasonic frequency that would be designedsuch that the spectrum scans the possible resonance of the initialscaling particles formed. This can be easily done by both the frequencychange on the ultrasonic signal and also varying the resulting harmonicswith the waveform of the signal such that the natural resonance of theparticles are achieved with very good certainty. This procedure is wellknown in testing electronic devices for electromagnetic compatibilityissues and performance. Since the timing logistic is designed to be doneduring the initial formation of the scaling, the mass of the particleswould be low and therefore the resonance of the particle is high andcould be amenable to ultrasonic pressure waves. After a dwell time ofmechanical cleaning, a flushing with large amount of water would be usedto carry out the particles removed from the walls of the deliverysystem. The duration for the mechanical ultrasonic cleaning is extendedwith occasional use of chemical cleaning in terms of reducing the PH ofthe water solution. Analysis was made on the assumption that withcontrolled metering of the delivered water, the water with knownhardness would deposit all the carbonates it carries with it because oftotal vaporization. The maintenance of the scale buildup maybe guided byan empirical test with results that determines the time threshold bywhich maintenance for the heat transfer surfaces have to be implementedbecause of undue degradation of the heat transfer property. The testdata from the literature and the predictability on the magnitude of thescale buildup because of the metering process of water delivery predictsa result that it would take a year to degrade the thermal conductivityof the system using water vaporization.

The general idea on how to implement the delivery of water forvaporization with consideration on minimizing water usage, scaling,maintenance and initial capitalization is addressed. There are twopossible implementations for the existing fin and tube condenserstructure.

FIG. (19) shows schematic of the metered water delivery. The schematicconsist of a dual tank 196 and 198 which are respectively the sourcetank from the water utility 190 and the pressure controlled tank 198.The water source tank is controlled by a float switch that regulates thewater coming from the utility. 200 is a small peristaltic pump able tobe driven in a bidirectional manner such that the water delivery iscapable of increasing or decreasing the pressure head. 222 is theperistaltic tube port for the water delivery pressure tank, and 224 isthe peristaltic tube port for the source tank. 226 is the port outletfor the pressure tank 198 where the water delivery to the tray 204 canbe closed with electric solenoid 202. The utility water comes in througha float and valve arrangement 192 and 194 to maintain automaticallysufficient water supply from the utility line.

The water delivery control is shown. 210 shows the temperature sensormade of thin wire of controlled length. 210 is shown with the wire gridarranged so that the sensor is exposed to the whole air flow area andautomatically sense the average temperature. For example in the diagramthe wire is wound sequentially 1, 2, 3, 4, . . . , 8, 9, 10. The blockdiagram and schematic of the water delivery sensing and control consistof the condenser fin and tube arrangement 208 and the water deliverytray 204 and peg arrangement 206 and the temperature sensors 210 and212. Precisely equal current sources 214 and 216 for each of thetemperature sensors 212 and 210 generates a voltage proportional to thetemperature measured by each sensor. The difference in the voltage whichis a measure of the degree of sensible temperature rise of the air flowis measured and amplified by 218. 220 receives the output of 218 andgenerates the power signal to control the flow of water in the dual tankwhich is connected to the water supply. Transfer of water from onechamber or the other is controlled by a simple peristaltic pump thatcould transfer water either direction for the purpose of maintaining awater head at the chamber for the water metering. The head of the waterin this chamber creates the flow rate needed for the metering of thewater for vaporization. FIG. (19) shows the structure of the dualchambers. The tank has to be situated above the water delivery nozzlesto establish the necessary hydraulic head H. Delivery to the nozzleequipments shall be with small tubing either metal or plastic.

FIG. (20) and FIG. (20 a) are the details on the structure of the waterdelivery tray and the uniform distribution pegs for the water droplets.204 is the water distribution tray. The water from the pressure tank 198comes into the tray through a entry port 244 where a layer of water filmforms above nozzles 240. These nozzles are uniformly spaced on the tray.The water pressure head generated in the water pressure tank providesthe necessary head to maintain a frequency of droplet formation. Thenozzle diameter determines the size of the droplets. FIG. (20 a) showsthe elevation of the structure to emphasize the regularity and thearrangement for the pegs with relation to the nozzle locations.

FIG. (20) shows one implementation of the water delivery trays. Thetrays would be installed above the condenser fins so that the meteredwater shall fall uniformly under the condenser coil axis. Upgrades shallbe custom activities and this might involve cutting a slot opening onthe plate covering and protecting the original condenser enclosure. Thetray material shall be selected such that it has high contact angle tohinder the formation of scales on the nozzles. The nozzle are uniformlyseparated with nozzle diameter selected such that metered water deliveryis in the form of droplets.

It is everyone's observation after a medium rain on a loose or even firmsoil that veins of channels are formed because of preferred paths forthe water flow. A similar occurrence could happen when there issufficient water volume for flow. The propensity for such phenomena ispreempted by using the second section for the water delivery. When theveins are formed on the condenser structure, the thermal efficiency ofthe process is degraded. The second structure 206 below the tray is aseries of pegs that again are selected to be of a material that has highcontact angle. The uniform location of the nozzles and the opening ofthe orifice determines the spacing of the pegs. When water droplets fromthe nozzle falls, the water drop forms spherical shape because of thehigh water surface tension. The peg location is such that the dropletsformed on the tray falls on the pegs. The high contact angle on the pegscauses the droplet to roll to either side of the peg. The next peg islocated such that the falling droplet will again encounter the next pegfalling with uniform probability to either side of the upper peg.Subsequent layers of pegs therefore will distribute statistically thedistribution of the water film to the condenser fins and tubes and avoidor slow down the formation of veins. The metering of droplets formed iscontrolled by the peristaltic pump that transfers water from one chamberof the tank to the other.

The effective implementation of the water metering delivery wouldalleviate the maintenance of the condenser fins and tubes for scalingbuildup. The probability of bio film formation is reduced because of thelimited presence of liquid water with the metering system. Also thecarbonates that the water delivering system carries would be predictablewhen water hardness are known. Therefore the maintenance and logisticson when it is done is predictable. Extrapolation from empherical testdata by others on condensers showed that under conditions of the worsecase hardness of water source, the maintenance for scaling buildup wouldbe needed in about one year. The empherical testing was done underconditions favorable for bio film buildup. Thus the interval stated isconservative and the maintenance frequency is practical and affordable.The maintenance for removal of the scaling is improved such that highvolume and low pressure water cleaning is adequate. This is because thebio film formation is avoided as much as possible with the watermetering process. Otherwise it would require more often maintenanceusing complicated maintenance equipment. Empherical test showed thatunder the formation of bio film, the threshold where the adhesiveproperty of the bio film is accelerated occurs approximately 2 months.The conditions by which this result was obtained are avoided in thisprocess.

The theoretical COP improves with decreasing ambient temperature,assuming the “temperature head” of the condenser does not change.However when higher cooling capacity is needed, the low ambienttemperature limits the available water vapor from the low temperatureair. Under this situation the air flow control would demand more airvolume. With the upgrade on the systems, this convenience for adjustmentis not available.

The vaporization process has the advantage assuming there is adequateroom to support water vapor formation for the cooling load. Thecapability of the air conditioning or refrigeration systems on lowambient temperature is degraded especially with large cooling systemsbecause of the magnitude of the saturated humidity at the lowtemperature.

This limitation is alleviated if the air flow is raised to a highertemperature than the low ambient temperature to increase the availablewater vapor content for vaporization. The procedure is to configuresections of the condenser to operate normally using the sensible heatair transport for convection. From FIG. (12 a) and FIG. (12 b) one cansee that heating and/or cooling first but with the air flow temperatureadjusted to a higher temperature, the capacity of the system isincreased.

The upgrade is implemented as follows. The block diagram of the upgradefor a central air conditioner condenser or refrigeration system is shownin FIG. (23 a). The existing condenser is conveniently divided intothree (3) sections by suitable baffling arrangement. Each of the threesections 210, 212, 214 are equipped with the water delivery system forvaporizations. These are shown as 206 a, 206 a and 204 b, 206 b and 204c, 206 c. A section is designated as the section that would make use ofvaporization for cooling. Each of the sections have the water deliveryvalve 114 a, 114 b, 114 c such that the system can be operated usingfully vaporization. Section (210, 204 a, 206 a, 114 a) is mechanicallybaffled to operate under vaporization when there is an inadequate vaporcapability because of the ambient environmental conditions. Thecondenser air flow from the fan has the baffle arrangement such that aportion is routed to section A. When sections of the whole condenser isdenied of water delivery by controlling 114 b, 114 c then the fan outputair flow would exhaust warmer temperature than the incoming ambient air.A portion of the warmer air is routed via the baffle arrangement tosection a. The warmer air would allow the condenser section to have alarger cooling capacity using vaporization because of the added watervapor cooling capacity.

The benefits in the reduction of the head discussed before iscompromised to the level where the needed cooling capacity for theequipment is reached. Still the vaporization augments the original airmaterial convection for the condenser.

If one were again to allow the application of the vaporization techniqueto another remaining and trailing section of the condenser, this willachieve the sub cooling which improves the capacity further.

Notice that FIG. (22) has an implied configuration where vaporizationtechnique is applied to the whole condenser equipment. Thus we couldeliminate the individual valve controllers and leave only one at themost.

FIG. (22) is the embodiment for an upgrade where total water delivery ismade on the full condenser fin and tube arrangements. 210 are theaverage temperature sensors, 204 a, 206 a, 204 b, 206 b, 204 c, 206 care the water delivery tray and peg structures. 220 is the opening forthe condenser fan air flow.

FIG. (22) is modified such that the various valves needed for individualsection control on water delivery is added as shown in block diagramFIG. (21) FIG. (23) shows the implementation which is the same as FIG.(22) except the shroud of baffle 230 is installed. The side panels of230 indicated as 232 could be removed so that full vaporizationoperation can be implemented.

The tradeoff of a compromise on the resulting efficiency and the noisefrom the fan air flow volume is a tradeoff decision that comes into thepicture. The full potential of reduction of the temperature head in thecondenser with the use of latent heat of vaporization may becompromised. When there is a need to warm up the air for thevaporization process, the procedure would lead to a higher “temperaturehead” than when we have complete latent heat of vaporization applied.The preconditioned air then is used for the latent of vaporization heatexchanger that would have the remaining cooling capacity to maintainthat effective temperature head. This will be a dynamic parameter thatwill be dependent on the ambient temperature, humidity and cooling load.This increased temperature of the air would lead to a demand for lowerair flow for the heat exchanger using the latent heat of vaporization.Since the latent heat of vaporization does not involve increase ofsensible heat and that the preconditioned air is exhausted to theenvironment, the condenser could be installed indoors where theoperating conditions are controlled and would lead to simpler controland uniform performance. The desired resulting efficiency for the systemcan be weighed with the benefits of a smaller unit because of the lowerair flow. This implies a physically smaller refrigerant enclosure wouldbe required. The smaller size enables users to enjoy the configurationof having the system indoors. The ramifications of indoor locations arediscussed in the third embodiment

FIG. (24) shows a schematic of the upgrade where full flexibility inselecting sections of the condenser could be made to operate onvaporization. It is similar to FIG. (22) except the addition of theelectronic controller for valve and motor control. It is used also forthe temperature sensor to determine the effectiveness and control of thevaporization procedure. The water delivery trays will have controllablevalves from the water delivery tank system. These are the valves 114 a,114 b, 114 c. Water delivery control and selection of condenser sectionsto operate on sensible or latent convection is implemented with thecontroller 240.

With the larger capability for cooling to the point that the airconditioner can be cooled to sub cooling region, the efficiency of thevaporization process for the air conditioning is more capable ofproviding improve efficiency in these situations where the cooling isneeded. In situations such as refrigeration systems the equipment has tooperate on lower ambient temperatures than usually required for airconditioners, The lower temperature limits the available room for thesame volume of air to absorb the cooling capacity needed from thevaporization process to accommodate larger cooling load. This is becauseof the lower saturated humidity at the lower temperature.

FIG. (24) shows the block diagram of the routing of the air flow bymeans of physical means such that the problem stated is alleviated. Theproblem at the lower ambient temperature could be alleviated with acompromise on the theoretical limit of achieving the full capacity ofefficiency that could be obtained from the vaporization process Thiswould be in between the ambient temperature and the “temperature head”addition to the original equipment. The block diagram shows a portion ofthe incoming air flow to be operating in the normal sensible temperaturecooling process that generates an increase in the temperature of theincoming air. Since no vaporization process occurs here, the relativehumidity of the outgoing air from this portion of the condenser is muchlower than the incoming air. The increase in temperature of the outgoingair opens more cooling capability from vaporization process. Acompromise on the magnitude of the temperature rise available with theSOP “temperature head” of 18.5 C is possible leading to increaseefficiency and performance for the refrigeration than is afforded by theoriginal configuration. The pre heated air flow for vaporization is usedfor the vaporization cooling process in another section of the overallcondenser cooling arrangement. The output from this section is thenrouted out and mixed with the output of the first evaporator operatingin the sensible temperature region of the air flow. The idea can beextended such that the water delivery is divided into three sections.The delivery system water metering control shall have the capability ofoperating all of the sections on vaporization. The first and the thirdsections could be turned on and off. Operation of mixing both sensibletemperature operation and full vaporization cooling process could beachieved with an overall higher system efficiency extended to a widerrange of ambient temperature and humidity conditions. FIG. (26) throughFIG. (28) inclusive are sketches of the implementation for upgrade usingthis process. The block diagram for the electronics control needed isshown in FIG. (29).

The equipment with the preheating chambers are shown in FIG. (26)through FIG. (29). The flexibility afforded by the scheme of threecondenser sections with the associated valves for water delivery ispossible only if an embedded controller were designed and implementedfor system input parameter measurements and control.

The technology use on the equipments for upgrade has the inherentreduction in efficiency with increase temperature and humidity. It is atthese situations where the efficiency performance is important becauseof the high usage.

Another method for water delivery is the use of spray nozzles suitablylocated to effect a uniform distribution of water spray. It is shown inFIG. (30). It is a more expensive procedure with the high pressureneeded and pump to for the pressure tank and associated valves. It is ofcourse a very practical option that is a mature process.

The upgrade process is inherently limited in scope. Since an airconditioning or refrigeration system is designed with all componentsconsidered, upgrading the performance of an equipment comprising thesystem will not necessarily result in the achievement of the objective.This is particularly true in the upgrade when the compressor is not aviable component to replace. The compressor is designed with theevaporator characteristics and the condenser in consideration. Improvingthe theoretical COP with vaporization process is one of the items thathave to be modified. Since the compressor physical characteristics arenot changed, there is a need for other control devices or strategies inorder to accommodate the improvement in the cooling efficiency of thecondenser for upgrades. The details on this will be presented as anotherseparate application. Actual tests have been made to verify that theprocedure as a companion for the usual hysteretic control on residentialand small air conditioning systems had been verified.

Description Second Embodiment

The second embodiment is the application on cooling computer chips. Thefabrication of computer chips and associated digital devices had beenfollowing Moore's law of speed and density. At the present, computerchips are dissipating over 100 watts. The fabrication of silicon deviceshave developed to the point that the limiting factor is the dissipationof the heat produced in the silicon chip. The reliability of anyelectronic is dependent on the operating temperature margin from maximumtemperature that the solid state devices operate in. The devices arerated from 125 C to at least 150 C depending on the technology used. Thefeature size (relative size of the basic transistor cell) has beenreduced considerably by several orders of magnitude. The technology isthat a system on a chip is the desired topology. With this the CPU,memory, dedicated hardware computation algorithm components such asDSPs, and other system functions that make use of the wide CPU bus aredesired for processing efficiency to be integrated into a chip. Thisarchitecture is beneficial in that the bottleneck of access to the otherdevices are not slowed down by any parasitic that are natural when theyare mounted on the PC board. The projection is that if this were done,the power dissipation of such devices could reach a power density of1000 watts per square centimeter. The cooling towers that are presentlyused in desktops are heat pipes where the thermal conductivity ismaximized from the chip to the heat sink. The heat sinks physical sizeusing this technology together with the implementation of convective airflow are larger than 100 cubic inch in volume. The fan speed generateapproximately 2.5 meters per second velocity for the air flow.

The process is applied to computer chip cooling enabling smaller thanthe 100 cubic inch volume to cool the projected 1000 watts per squarecentimeter power density. FIG. (25) through FIG. (34) is animplementation following the procedure discussed above.

The embodiment is such that practical considerations are included. Theinvention does not preclude other means but the basic idea of applyingthe maintenance of good thermal conductivity path with suitablepresentation of water for the vaporization process.

There is a base 260 such that when the heat sink module is installedwould be mounted to the computer chip. FIG. (26) is an elevation and topview of the heat sink. It would be mandated that the material which inall probability is metal should have the highest thermal conductivityallowed with practical economic constraints applied. It consist of threepieces. 260 is the bottom block. It has mounting means such that itcould be mounted with the computer chip. The mounting for the block isshown such that the heat sink orientation is vertical with the otherconfigurations that the PC board might be oriented. That is there ismounting provision on the bottom of the block and the side of the block264. This block shall have the precautions needed before such that theair gaps that are present in the interface between the computer chippackage and this block are minimized with thermal compound application.This block is configured such that the other part of the module could bedetached easily for either maintenance or replacement. This is necessarybecause of the scaling problem that is inherent with the process.Strategies for the design of the heat sink for maintenance andreliability. Also the second block 262 attachment is designed for easeof replacement or maintenance. Block 262 has the chamber where thevaporization occurs.

264 consist of a port for input for air flow. The heat sink has thecapability of having the temperature higher than ambient because of thehigh temperature tolerance of the silicon computer chip. The coolingprocess therefore is to initially warm the incoming air. The highconductivity block 264 has a labyrinth of air passages as indicated incross section view FIG. (28), FIG. (29), FIG. (30), FIG. (31) and FIG.(32). The air flow temperature is raised during its passage throughthese labyrinth of holes. It is not shown in the figures that there isan associated air flow pump externally that pushes the air for therequired air flow. This control is provided by an external embeddedcontroller. The temperature sensor that is needed to maintain themetering of the water are 266 a and 266 b. The sensors are designed in asimilar manner as previously discussed in the air conditioner systems.An averaging feature is designed in. The circuit is similar forconverting the temperature differences to control the water deliverysystem 260 block has an input port 270 for the ambient air. FIG. (28)shows the bottom of the labyrinth of holes. There are chambers thatserve as conduit for the incoming air to the holes running vertically onthe block. Similar network of chambers acts to receive the air flow ontop of the block. It is exhausted to the bottom of block 262 and servesas the conditioned air flow for the vaporization. FIG. (31) is a viewlooking towards the interface to block 260. 310 shows the need foreffective seal at the interface between block 260 and 262 to avoid anyair leaks When the input air is warmed up, the capacity for coolingincreases because of the larger amount of water vapor air can support.It is also beneficial in another way in that the volume of air needed tocarry the transport material of water vapor is less.

262 as shown in FIG. 33 contains regularly spaced fins to convey theheat flux to the water film for vaporization. The effectiveness of thevaporization is obtained by controlling the air flow velocity or volumeand temperature. Temperature sensors 266 a and 266 b when driven byequal and constant current sources would have voltage differencesproportional to the difference in temperature. The effective circuit issimilar to what was implemented for the air conditioning condensers. Thetwo temperature sensors are mounted on 268 which is a detachable sidecover for 262.

FIG. 34 shows details on the water delivery to the fins. The deliveryconsist of a sewn fabric 352 and 350 embedded tubes capable ofwithstanding the temperature of the fins. The fabric has to have theproperty of porosity. For example a possible candidate is the name brandGORE TEX commonly used in garments and sportswear. The fabric has avaporization is close to the vegetation transpiration rate. The fabricis sewn with the tubing such that it would form a system of socks thatwould hug and enclose the metal heat fins. Stitching holes have to besealed. There would be some structure 354 to help ease the installationfor repair or manufacturing. 356 and 358 serve as drain for water as apreventive measure. 356 is a trough at the bottom of the fins that hasnatural slope for water drain. The delivery of the water to the watersock network is on a port also on the detachable cover 268. The air flowexhaust port is 320 and the water delivery entry port is 322. Also shownis 324 as the connections for the temperature sensors. The drain channel358 may or may need a drain exhaust but if there is high reliability onthe water delivery control, then a liquid water sensor detector would beenough. Another alternative would be to have desiccant capable ofabsorbing non vaporized water to be temporarily absorbed and then becomepart of the vaporization process.

There would be situations where smaller volumes and possibly highercooling capacity requirements would be needed. The volume of the heatsink can be reduced if the vaporization rate that is required by theheat flux is supported physically by the surface for the diffusion.Together with this is the rate of transport provided by the air flow.The diffusion gradient can be optimized by the temperature of the airflow to provide a larger difference in the vapor pressure from thevaporization surface of the water film to the airflow.

The temperature of the air as pre conditioned by the labyrinth ofpassages in the heat sink body may not be sufficient under some of thestated conditions to affect the low vapor pressure needed for thecooling load, External heating could be implemented to achieve this.

The latter requirement could be alleviated by implementing auxiliaryheating external to the heat sink to augment the physical limitation ofproviding the chamber for heating within the heat sink. This procedurewould provide the flexibility of extending almost at will the capabilityof the heat sink. The process of preheating the air adds a favorablecontribution to this problem. When the air is heated, the saturationlevel for water vapor rises exponentially with the temperature rise.This implies that lower volume of air flow is needed to carry the watervapor product of vaporization. The silicon devices are capable of atleast reaching 125C. With proper care and design on both the interfaceto the computer chip and the pre heating higher temperature for the airflow could be achieved. This further reduces the rate of air flowneeded. Tradeoffs are the reliability issue desired for thesemiconductor. The cooler the silicon more reliable and longer life forthe device. The other factors are aesthetic on the practical temperaturefor the output air flow, and requirement for better materials to handlethe higher air temperature. The design of the pre heater will dictatethe volume of the heat sink. The pre heater should not eliminate much ofthe highly conductive material used for the heat sink to the point thatit reduces the thermal conductivity from the computer chip to the finsto which the water film is introduced. The fins should be as short aspossible to reduce the effective thickness of the fins. Thus under somecircumstances the external preheating of the air flow is moreacceptable. This is true from the point of view that the power needed toheat the reduce volume of air flow is small compared to the benefitsthat would accrue with the cooling process. The fins total surface areahas to be designed such that the diffusion rate and the capacity willnot be limited by the area used for the diffusion to convey the heatflux. Increasing the fin surface area and minimizing the gaps betweenthem would be parameters to be considered. Decreasing the gap betweenthe fins makes the air flow laminar. If the boundary layer is desired tohave as much vapor pressure gradient as possible to enable the heat fluxcapacity needed, then the air flow should be adjusted correspondingly.Again in order to assure that the water delivery is metered to preventsaturation in the air flow chambers.

Other procedures of implementing the delivery of water are possible. Theconsiderations on scaling buildup are one of the factors of importance.These are subjective decision and amenable to various degrees ofvariation.

For example the water delivery could be via other means of transpirationusing other topologies of the relationship between the water containervessel and its introduction to the air flow stream. Compromise on theease of maintenance of scaling problem to the economics of replacing thecomponents are tradeoffs that have to be considered. Also themaintenance as a result of scaling does not have to require maintenancebut if economically justifiable a strategy of throw away replacement.The circuit for the decision on how the air flow is controlled aresubjective and not absolute. Therefore the process indicated in thisapplication would include such possibilities and variations

Another version of the heat sink would be a modification of FIG. (26)and FIG. (26 a). The technology called Peltier heating and cooling whichdepends on the Seebek effect on semiconductors are well developed forcommercial applications and are economically viable. The implementationof added external heating is a practical and natural extension of usingthe Peltier effect heating elements. Packaging them would be alsoamenable to the size of the heat sink because they can be small enoughand that the energy requirement for the pre conditioning of the air flowis minimal on heating and/or cooling capability The Peltier heatingelements could be mounted on the side of the side sink as an extensionof FIG. (26) and FIG. (26 a) where they would be attached modules on theside of main block 260.

Description Third Embodiment

The third embodiment is an application of the process to new airconditioning and refrigeration equipments.

Air conditioning or refrigeration systems are system level type ofdesigns. It is different from the upgrade discussed previously becauseall tradeoff are available to be considered together as an aggregate tobe weighed with all attendant requirements of economics, capitalization,reliability, maintenance, aesthetics. This section as an embodimentshall focus on the changes that could be implemented with the advantagesof vaporization in new designs for air conditioning or refrigerationsystem of various sizes. Different applications shall be touched on fromsmall ones like portable units, central type as used in residentialunits and the large units that are for example represented for thecondenser cooling by the use of water towers. Embodiments that typicallywould apply the various items discussed previously shall be considered.The implications of the advantages provided by the use of vaporizationshall also be discussed.

Considering only the condenser and also using the same fin and tubetechnology that is very mature and economically viable, the followingare advantages in implementing the process. The other developments thataddresses the enclosure for the refrigerant to improve its thermalconductivity which is a major portion of temperature head with thisprocess could be adopted when the manufacturing process and volume is atthe point of economic viability. It does not of course preclude theactivity of devising other implementation of the condenser structureconsidering the inherent physics of the vaporization processrequirement. For example modules that are extruded with chambers for therefrigerants that do not necessarily depend on the linear feature of theflow of refrigerant could be designed. Parameters to optimize thelabyrinth that would be created in this modules had been studied byothers using the existing copper tubes but adapted to other internal andexternal configurations. It is known that for a given geometry withconsiderations of thermal conductivity and problems of liquid and vaporglobs on the tubes, there exist optimal length and dimensions Theimplementation of the vaporization process is not altered because ofthese variations in the physical nature of the refrigerant flow andenclosure.

The implementation of the vaporization process with the attendantaddition of various parameters for controlling the system adds toflexibility, reliability, more effective maintenance program, robustnessand capability of synergistic operation with other energy usingequipments in the area or home.

The implementation also automatically reduces the size and air flowneeded for the cooling unit. Using the fin and tube condenser as modulesto create easy maintenance. It enables a hierarchy of cells or modulesas basic units for building and upgrading systems. This enables theelimination or extension of economic losses due to system downtime formaintenance. The flexibility afforded for upgrades, e.g. the rule thatthere is always a diminishing capability on large computer systeminstallation would make upgrades on cooling capacity easier and could bepredicted. This hierarchical structure would enable seamless additionsfor increase cooling load requirements. The upgrades could beimplemented without system downtime since tapping into the existingsystem could be designed such that such operation is seamless. Theprogressing building block of FIG. (35) of creating the system enablesthe scheduling of the maintenance of portions of the system withoutaffecting the capacity and performance required of the system. Also theprocess enables the location of the condenser indoors and reduction ofsize and capitalization cost.

The basic cell module as an architecture can be as shown in FIG. (21).The source of water head can of course be modified together with thesolenoid valve with other methods. However the basic topology of beingable to mix sensible and latent heat of convection transport is shown inFIG. (21). A basic “cell” for example could be 10 ton capacity systemfor large systems. Systems for smaller commercial systems can have“cells” of smaller capacity.

The implementation of the control, both from the cell level and systemlevel might be seamless to accommodate other existing controllers if thebasic “cell” structure has an independent controller with the capabilityof communicating with the rest of the “higher level cells” hierarchy.Breaking up the demarcation between the other parts of the refrigerationsystem such as the compressor, air handling systems will also beaffected with regards to the architecture of the system but I am notaddressing these issues.

Air conditioning systems with externally located water towers could beimplemented with smaller sizes that could be located indoors. The systemindoors can be designed to have a hierarchy of components that woulddistinguish the level of both cooling contribution and maintenancesegmentation. The basic condenser cell shall have a minimum coolingcapacity that could be configured to have embedded pre heating (preconditioning) or a basic condenser which will have all condenser finsand tubes to be operated with vaporization with the use of a preconditioning chamber FIG. (21) and provide the pre conditioning ofcooling and/or heating as discussed previously. This process enhancesthe efficiency and capability of cooling capacity and performance toambient temperatures that are high with corresponding high relativehumidity. The inputs to these pre conditioning chambers shall havedampers to regulate the portion of ambient outside air or indoor air forreplenishment. The plumbing of the air flow and also the water deliveryvalve control have to be implemented per situation of type of preconditioning.

FIG. (21) is a concept for a general pre conditioning of air as sourcefor the condenser using vaporization for cooling. We know that warmingup the air increases the water vapor capacity of the air and allows usto use less volume of air with the controller to transport the heatflux. This was applied to the computer chip cooling and enabled us tocool and get rid of high heat flux. This is a case in large systemswhere a general air pre conditioning is applied, i.e. both cooling andheating of the air is used for pre conditioning. FIG. (21 a) is a curvethat justifies the concept. The equation for saturated water vapor attemperature i is given on first line. Ilow is the number of degrees C.that the cooling is performed. The curves show when the air is warmed inthis case 3 times ilow above the ambient temperature. The total energyto cool and heat for pre conditioning the air is trace 5. It consist ofthe latent heat to condense to the dew point extra water vapor at 90.5°F. with a relative humidity of 80% and the sensible heat of lowering thetemperature by 4.5° F. and raising the temperature by 13.5° F. above90.5° F. The enabled capacity for cooling with the transpiration withthis process is trace 2. The graph shows that if the cooling 9F and warmthe air temperature by 13.5 F above original ambient (90.5 F), then 1cubic meter per second air flow would enable 100 kilowatts of coolingwith transpiration. The SOP for the cooling using original equipmentwould require approximately 7 kilowatt of fan power. The effective powerthat is used on the air volume is approximately also 7 kilowatts.However since we are using an air conditioner with a given COP, thenassuming the air conditioner has a COP or 3.5, then the actual powerusage is 2 kilowatts. The advantage is not only on the net powerconsumption but also it enables lowering the air flow by a factor of 25for the vaporization Thus the air pre conditioning is beneficial both onenergy and also lower the air flow with reduction in physical size ofthe condenser

The equipment used for this would be a standard air conditioning system.A tighter control on the temperature and monitoring the cooling to avoidfreezing may be alleviated with an external controller 518 where sensorinformation from the cooled chamber and the warm chamber are obtainedfrom sensor 508 and sensor 510 respectively. The cooling equipment airflow are separated as typical for air conditioners. The cooled airoutput 521 is routed from the output of the evaporator 520. The inputair to the evaporator consist of metering mixture of air from the cooledchamber 526 and the outside ambient air 500 and the air flow output fromthe transpiration equipment with the dampers 504 and 502 and 506.Similarly the warm air is circulated through the condenser. The inputair to the condenser is 516. The air pre conditioning equipment is theusual convective type condenser and evaporator with air as the transportmaterial. The cooling strategy is to bring the room air temperature to alow level with the intent of removing all water vapor such that thecooled air is at its dew point. The warm air chamber 528 on the otherhand is the air that is involved with the condenser. This warm airchamber will circulate the air just like the evaporator 520 in the coolchamber. Assuming care is exercised such that further heat energy lossesin both chambers are mitigated, then the energy required would be asdefined by the COP of the equipment. The air pre conditioning chamber524 consist of cooled air chamber 526 and a warm air chamber 528. Theair conditioner used for the air pre conditioning circulates airseparately through the evaporator (cooled chamber) and the condenser(warm chamber)

Rough economic study had been made on applying the process on new plantsand the return on investment showed promising benefits. They arecontributed both by the initial reduction of capitalization and also onthe large savings on the recurring cost because of the advantages ofefficiency and maintenance.

The method followed in the process for addressing the problems ofscaling reduces the recurring cost of maintenance and also avoids orlogistically delay total system downtime for maintenance.

The implementation of the different aspects of the process to newequipments would result to the following:

Portable Air Conditioners:

-   -   (1) Smaller size.    -   (2) Portability to the strict sense of the word because of size        and some cases the convenience of eliminating the umbilical        cords associated with the usual VCRS type portable air        conditioners air flow.    -   (3) Indoor location could benefit from the side effect from the        vapor output that could effectively improve comfort level        depending on the environment.    -   (4) Economic benefits since local cooling on demand can easily        be implemented.    -   (5) Portability and extension of cooling capacity of a given        unit with the property of preheating is available.

Residential Central Air Conditioners

-   -   (1) Smaller size.    -   (2) Indoor location with advantages of consistency of        environment for operation and improvement of reliability and        life. Reduce volume of air flow is an advantage to lowering the        noise level indoors.    -   (3) Synergistic operation with other energy using devices at        home. Higher Efficiency.    -   (4) Better control for comfort level.    -   (5) Extension of cooling capability because of implementation of        preheating feature.    -   (6) Seamless increase of cooling capacity. This is very common        with computer server rooms.

Utility and Other Large Cooling Systems

-   -   (1) Modular cells leads to manageable maintenance that        logistically could complete full system maintenance regularly.    -   (2) Modular cells does not affect the local downtime of the        smaller modules comprising the whole system.    -   (3) Condenser cooling system could be completely located        indoors. This arrangement lends further control leeway for the        vaporization system because choice of air flow source could be        chosen from either the conditioned indoor air or outdoor air.    -   (4) Control to accommodate demand for cooling for the whole        system leads to flexibility and economic operation.    -   (5) System could be located indoors and avoid all the        disadvantages discussed in connection with bio film and scaling,        degradation of equipment because of exposure to the elements.        The procedures which are generally expensive and not        environmentally friendly on treatment of cooling water are        alleviated because of the application of the metering process.    -   (6) Reduction of initial capitalization for new plants.    -   (7) Reduction in size. For example it is very doable to reduce        the volume size of the active components for the condenser        compared to the water tower cooler by 50 times.    -   (8) Other additional benefits on reduction of losses such as        energy for pumping the cooling water in the towers, the large        expense on water replenishment because of the evaporation of        water not involved in the vaporization process, reduction in        energy usage for air flow because of the reduction in air flow        requirements.

1. A system to deliver water for vaporization and control of theconvection mechanism to transport the water vapor product for coolingincluding: a. feedback control means on water delivery rate forvaporization, b. control means of air flow for transport of vaporizationproduct, c. sensors to measure temperature and d. means to control waterdelivery to provide water and fan speed to effect the heat transferutilizing only vaporization and avoiding encroaching on heat transferinvolving sensible heat of water.
 2. The system of claim 1 furtherincluding a temperature sensor that averages the temperature on the airflow opening.
 3. The system of claim 1 further including water deliverymeans to control the rate of drop formation.
 4. The system of claim 1further including water delivery means to deliver and form a uniformwater film on a hot surface.
 5. The system of claim 1 further includingmeans to control scaling.
 6. The system of claim 1 further includingmeans for maintenance to prevent reduction in efficiency due to scaling.7. The system of claim 6 further including means to use ultrasonic wavesusing scanning frequency of waveform drive together with duty cycle toenable mechanical dislodge of small bicarbonate deposit.
 8. The systemof claim 6 further including means for selection of materials for trayand peg for the water distribution to have a high contact angle.
 9. Thesystem of claim 8 wherein the materials are one of polycarbonate andTeflon material.
 9. The system of claim 1 further including air flowvelocity control to complement and/or function together with waterdeliver control.
 10. The system of claim 1 further including means tocontrol the air flow temperature by pre conditioning of heating andcooling to minimize air flow for transport by convection and reduce sizeof heat transfer structures.
 11. The system of claim 9 further includingmeans to arrange sections of a condenser to operate in either air orwater vapor for transport mechanism by using sensible air flow from airconvection section to precondition air flow for efficient vaporizationprocess with other section if a compromise on full benefit ofvaporization under some ambient operating conditions.
 12. The system ofclaim 10 further including means to pre heat air for computer chipcooling.
 13. The system of claim 10 further comprising means to precondition air for computer chip cooling using Peltier heating andcooling semiconductor device.
 14. The system of claim 1 furthercomprising means to pre condition air for large cooling loads usingvaporization.
 15. The system of claim 1 further comprising means to havedistributed cell condenser modules on very large capacity coolingsystems to minimize system downtime.